DE2714674B2 - Superalloy with high fatigue strength - Google Patents

Description

The present invention relates to iron-based superalloys with high fatigue strength, Chromium, molybdenum and nickel containing no more than 0.3% by weight of cobalt and good mechanical Properties within a wide temperature range, high corrosion resistance to chemi see attack in the presence of aggressive media and have a high resistance to various erosion processes and therefore in particular for the Nuclear technology are suitable.

Of the alloys that meet these application criteria, the alloys with high Cobalt content is known for its good resistance to chemical corrosion and to erosion however, cannot be used in or around nuclear reactors as they are due to their cobalt content are strongly activated under the influence of neutrons.

For a classic superalloy, for example, at 60

up to 65% cobalt, such as alloy No. 1 in Table I ₁ which has been used on a large scale for 40 years,

ίο the basic element cobalt under the influence of Neutrons are converted into cobalt-60, which is due to the induced radioactivity emits a high-energy y-radiation and an extremely long half-life The neutron capture cross-section of cobalt is 37 "barns" (b).

On the other hand, this alloy is used for a variety of uses outside the scope of Nuclear technology can be applied because of the costly cobalt price.

They are also alloys with a high nickel content like the ones in the table! indicated alloy No. 2, known to contain about 70% nickel. However, these alloys do not have sufficient corrosion resistance. Thus, this widely used alloy No. 2 was ^{investigated at 350 °} C. in contact with demineralized water where, as is to be expected, it is corroded and forms a green nickel hydroxide layer.

On the other hand, this alloy is one relative

jo has a high boron content, for applications on the Not suitable for nuclear engineering as boron is a dangerous neutron catcher. The neutron capture cross-section of boron is 750 "barn".

There are also alloys based on i ") iron, chromium and molybdenum known, such as those in FIG Alloy No. 3 given in Table I below.

In these alloys, the excess carbon (2.9 to 3.7%) forms chromium carbides in an extremely hard iron-molybdenum matrix which shows good friction • to hold Cn in a dry state. However, these alloys are flawed in hot or corrosive environments due to the lack of cobalt or nickel.

These alloys are capable of with respect to their Elastizi-4 ^r. did and their stretching before the breakage was unsatisfactory.

Table I. alloy alloy Alloy (Mean values) number 1 No. 2 No. 3 1.20 1.0 2.95 28 20th 18th carbon I. 3.5 0.85 chrome I. - 0.20 Silicon - - 16 manganese - - - molybdenum Niobium tantalum 4th - - (Alloy) - - - tungsten 1.5 rest - zirconium - - 2 nickel <3 5 rest Vanadium 65 traces <0.2 iron cobalt

continuation

alloy
number 1

alloy
No. 2

Alloy No. 3

strain
Hardness (RWC)

Hardness distribution
on the blank

2%
40/44

very
evenly

45/50

little
evenly

66/68

very
evenly

The object of the invention is to create a superalloy with high fatigue strength, which can be used in particular in the nuclear technology sector and which

- Has a good hardness both in the cold and in the heat (300 to 800 ⁰ C), which is higher than that of the known alloys based on Koba't or of alloys which contain more than 40% nickel ,

- has a resistance to chemical corrosion equal to or greater than in all cases that of known and used alloys, and in particular corrosion resistance against overheated steam, exhaust gases from engines or gas turbines as well as the usual corrosive ones Shows fluids or liquids

- Excellent frictional properties in the cold and in the heat in a wide variety of environments and shows in the most diverse contacts that are equal to or better than those of known and commonly used alloys; and especially a good persistence and a good one Frictional behavior when used in the field of nuclear engineering or in contact with Demineralized, heavy, or pressurized water, steam, or liquid sodium shows in nuclear reactors even in the primary circuit;

- Has physical and mechanical properties that are comparable to those known and commonly used alloys, d. H. a satisfactory modulus of elasticity, a satisfactory one Tensile strength in the cold and in the heat, adequate hardness in the cold and in the heat that allows the alloy to deform well while still making the material a good one Rcibüiigsver — lögen owns, and

- excellent weldability with all Structural steels (with the exception of titanium steels or steels with a high chromium content and Carbon content).

This object is now achieved by the alloy according to the invention with high fatigue strength, which thereby is characterized in that it consists of 0.2 to 1.9% carbon, 18 to 32% chromium, 1.5 to 8% tungsten, 15 to 40% nickel, 6 to 12% molybdenum, 0 to 3% niobium tantalum, 0 to 2% silicon, 0 to 3% manganese, 0 to 3% zirconium, 0 to 3% vanadium, 0 to 0.9% boron, less than 03% cobalt, The remainder is iron and impurities from the manufacturing process consists

According to a first preferred embodiment of the invention, the alloy consists of 0.2 to 1.9% Carbon, 18 to 32% chromium, 1.5 to 8% tungsten, 15 up to 40% nickel, 6 to 12% molybdenum, 0.1 to 3% niobium tantalum, 0.1 to 2% silicon, 0.1 blr 3% manganese, 0.1 up to 3% zirconium, 0.1 to 3% vanadium, less than 0.3% cobalt, the remainder iron and manufacturing-related Impurities.

According to a second preferred embodiment, which is aimed in particular at alloys that should not be exposed to a neutron stream, these alloys with high fatigue strength consist of 0.2 to 1.9% carbon, 18 to 32% chromium, 1.5 to 8% tungsten, 15 to 40% nickel, 6 to 12% molybdenum, 0.1 to 3% niobium tantalum, 0.1 to 2% silicon, 0.1 to 3% Manganese, 0.1 to 3% zirconium, 0.1 to 3% vanadium, 0.1 to 0.9% boron, less than 0.3% cobalt, the balance iron and production-related impurities.

Further embodiments, objects and advantages of the invention emerge from the following Description in which reference is made to the drawings.

In the drawings shows

F i g. 1, the hardness in the heat of the alloys according to the invention as a function of the curves from the temperature,

F i g. 2 the results of the friction study of the alloy according to the invention on the basis of a curve,

Fig. 3 to 6 microphotographs showing the structure of the Alloys according to the invention illustrate and

7 is a photomicrograph used for comparison purposes the structure of cobalt alloy No. 7 in Table II reproduces.

In the following table II the compositions of three alloys according to the invention are given as examples (Alloy No. 4, Alloy No. 5, and Alloy No. 6) and a cobalt alloy (Alloy No. 7), which essentially corresponds to alloy No. 1 in Table I, and for comparison purposes serves.

Table Il alloy ι to I. alloy ι to 1.50 alloy ι to 0.50 Comparative I, 20th until 28 until 30th until 31 alloy 30th No. 4 until 1.2 No. 5 until 1.2 No. 6 until 1.2 No. 7 I, 2 0.70 until I. 1.20 until I. 0.20 until I. 0.9 to I. carbon 24 26th 27 26 to chrome 07 0.7 0.7 0.7 to Silicon 0.5 0.5 0.5 0.6 to manganese

5 9 27 14th until 674 Alloy! b 12th Comparison - I. until 2 alloy - I oilset / ιιημ alloy I. until No. 6 I. No. 7 - alloy until 9 to 3 3 to 5 No. 4 I. until I to ! 6 to 36 No. 5 until 0.5 to 20th 1 to 1.5 molybdenum 0.5 to (i 9 1.5 to 60 to 65 Vanadium 0.5 to I. 2 (1.5 to <3 Ni (> b-T; int; il 3 to 0.5 I. 16 to tungsten 0.5 to 3 <(1.3 zirconium Ώ to 0.5 I. rest nickel < 0.3 26th 30th Kobiilt rest <0.3 solve rest U, .Γ <^ a ^

The three basic elements of the invention Alloys are chromium. Nickel and iron.

The diagram of the fundamental equilibrium is that of the nickel-chromium-iron system, which deals with the relative Proportions of these three elements changes.

These alloys are generally in the form of the γ + ix phase. The δ-phase occurs only sporadically and depending on the iron / chromium ratio.

These alloys crystallize ^v stem of the hexagonal closest packing of spheres in the S. In the range of the stated contents of these three elements one can develop the desired phases and avoid the presence of only the o-phase, the matrix of which is weak.

With certain combinations one can use the λ + o-phase achieve. The typical example is alloy no. 6, which in the presence of the λ + σ phase in It is remarkably suitable for castings which, in terms of their frictional behavior in heat and in the cold are beneficial in particularly difficult conditions.

The position of the boundary between the two phases (γ + α) in turn depends on the rate of cooling.

Indeed, the allotropic transformation of the corresponding alloys are influenced by strong thermal hysteresis. The transition from y-state to α-state is never complete despite thermal treatments with slow temperature decrease.

This means that the alloys according to the invention in the case of these phases show practically no transition point (with the exception of alloy No. 6, which has a transition point of 785 ° C with respect to the * + σ phases), so that a rapid or slow cooling has little effect on their properties.

Combining alloy # 7 (with a high cobalt content) with alloys # 4 and # 5 compares, one observes the same physical reactions with respect to the fast or the slow cooling.

The alloys according to the invention also contain 6 to 12% molybdenum and 1.5 to 8% tungsten. These precise contents of molybdenum and tungsten make it possible to adjust the amount of metal carbides obtained in order not to form excessively carburized zones in the already hard matrices.

Other elements, such as vanadium, zirconium, can also be used in the alloys according to the invention. Silicon. Manganese, niobium-tantalum and boron may be included.

The vanadium acts in an amount between 0.1 and 3% on the ferrite bond and also on the formation of the Carbides a. So that it can take on the latter role, it is made of stainless, completely austenitic Le; 'e7iingen (with high nickel content and possibly a manganese content), it being assumed that this element is a favorable one Causes aging, which justifies the use of the alloy for purposes involving high temperatures from 400 to 800 ° C can be used.

Furthermore, extremely fine and very hard vanadium carbides are found in the final phase of the transformation homogeneously distributed in the mass of the alloy. Hamlet still This results in a secondary hardening of the alloys by vanadium, which is a consequence of the precipitation of VdC < on the dislocation areas.

The homogeneous germ separation in the matrix results if the vanadium and carbon contents are sufficiently high, this also has a hardening effect.

Furthermore, with the stated contents of vanadium and carbon, the blocking of the Grain compounds through a precipitation of vanadium carbides and not through a precipitation of Cementite caused to be.

The use of zirconium in amounts of 0.1 to 3% makes it possible to achieve this in a noticeable manner To reduce the gas content by removing the nitrogen and the sulfur content of the alloys. Bern Pouring, this element acts as a deoxidizer. On the other hand, it does not affect the neutron flux, because this element has a very small neutron capture cross-section

The 0.1 to 3% niobium tantalum content of the alloys according to the invention (as a master alloy) results in a stabilization of the carbides, a refinement of the grain and a reduction in intergranular corrosion, an improvement in the properties of the alloys at high temperatures (400 to 800 ^° C.), an improvement in the welding behavior and, through the formation of niobium carbides, an improvement in the flow behavior of the superalloys, which have a considerable nickel content.

The presence of silicon in amounts of 0.1 to 2% increases the corrosion resistance of the Alloy in certain acidic solutions with reducing

ability improved. Continue to practice this element has a beneficial influence in potting, where it takes on the role of a deoxidizer.

At the used amounts of 0.1 to 2%, the manganese exerts an influence analogous to that of nickel especially with regard to the tendency to stabilize the austenite phase. The manganese improves also!:. the corrosion behavior of the alloys in the heat. It also reduces the formation of cracks, especially when welding or hard alloys to be deposited. When the alloy is formed, the manganese acts as a deoxidizer.

The boron favors the melting of the mass at contents of 0.1 to 0.9%, since it reduces the melting point of the Alloy reduces what is important for welding rods for build-up welding or spray powder is.

The alloys with this composition can usually be made using conventional Melting process are produced. For example, they can be used in an induction furnace or in a vacuum arc furnace produce.

They can be cast using conventional casting methods, in particular by casting in Sand or metal molds, by casting using the lost wax method, by direct casting, by centrifugal casting etc. These alloys can be used for the manufacture of solid objects with small or large dimensions can be used without the formation of cracks or abnormal Segregation phenomena is to be feared.

The alloys according to the invention have good mechanical properties. In particular is hers Ductility in hot and cold conditions comparable to that of the best cobalt-based alloys. Furthermore, in the specified composition range of the alloys, their elongation at break varies from 1.5 to 3%. The hardness in the cold is in the warm quite high. The tensile strength in the heat is just as great as that in the cold.

In FIG. I shows the values of the Vickers hardness in the heat of alloys No. 4, 5, 6 and 7 as a function of the temperature (in ° C.). It can be seen that the hardnesses of alloys No. 5 and No. 6 are better compared to the cobalt alloy No. 7 and that the hardness of alloy No. 4 in the heat is also better when the temperature is above 300 ^° C lies. Regarding the hardness of the alloys of the present invention, it should be noted that alloys Nos. 4 and 5 normally behave like cobalt alloy No. 7 with respect to the increase in carbon content or with respect to the increase in the content of metal carbides. As a result of this, a hardness is obtained which increases proportionally to the carbon content, and this is evident with a coarsening of the structure, which can become crystalline if the carbon-chromium contents are too high.

In contrast, the hardness of alloy No. 6 does not increase with the carbon content. As a matter of fact runs in this one formed from the λ + o phase Alloy has the carbon curve inversely to that of the other known super alloys. So that corresponds Curve with a carbon content of 1 to 0.20% of a texture that becomes finer and finer as the hardness increases with a reduction in Hps carbon dioxide content "; increases. The most suitable plateau is found between a carbon content of 0.20% and 0.50% Characteristic curve, since the alloy obtained is hard in the cold and in the heat. is very resistant to oxidation and is ductile enough to be potted or deformed.

Alloy No. 6 thus proves to be very interesting. However, it can be used for hard coat layers not recommended as thinning the alloy with the backing steels will reduce their equilibrium diagram disturbs. In this application too, it is not preferred to use the alloys according to the invention to use those which have an increased nickel content and a lower iron content, d. H. Alloys, those for the application of metal layers with the help of conventional procedures and without thermal aftertreatment are suitable.

In the following Table III are the results of the physical-mechanical examinations of the alloys No. 4, 5 and 6 indicated. The values listed in this table represent mean values that can be obtained with various alloys that fall into the compositional range of alloy nos. 4, 5 and 6 fall. For comparison, the results obtained with alloy no. 7 are also obtained in this table based on cobalt.

Table III

modulus of elasticity

(N / mnr)

Room temperature tensile strength hardness

(N / mnr) (HRC)

strain
δ density
(g / cm ³ ) At 600 C
Tear resistance
in the warmth
<> R
(N / mm ³ ) strain
δ 2 / 2.2 7.9 530 ± 30 2/3 1.8 / 2 8.3 500 ± 30 1.8 / 2.2 1.8 / 2 7.7 480 ± 30 1.7 / 2.1

Alloy No. 4,220,000 ± 3000
Alloy No. 5,248,000 ± 2,500
Alloy No. 6 195 500 ± 2500

610 ± 30th 38
42 570 ± 30th 42
46 570 ± 30th 46
50

I'lMlsCt / lHlU

ίο

F.lusti / .itiilsmodul room temperature

Tensile strength lliirle

(N / mm-)

(N / mm-)

(HRC)

Elongation density

At 6 (X) C

Tear resistance
in the warmth

(g / cm- ') (N / mnr'l

Elongation δ

Alloy No. 7
(Cobalt)

228,000 ± 3500

concerned with the

l'cndel-Elasti / .itiits-

measuring device

790 ± 30 -

40

44 2 / 2.2

8.4

690 ± 30

investigation
carried out
with the micro / ug device

In the following Table IV are the expansion coefficients of alloys No. 4, 5, b and 7 at different temperatures. This coefficient of expansion is defined as follows:

ι (mean)

I /

HH ₁ , '

No. 4

No. 5

No. 6

V CIgICK (IN-

alloy

No. 7

7 (H) C 9.85 13.05 10.50 16.1
800 C 10.15 13.55 10.50 16.2

/ ° = length at room temperature

AI = change in length

θ = temperature

θο = room temperature, d. H. at the carried out

Investigations 20 ⁰ C
λ is given in μ per meter per ° C (μπι / ιη · ° C).

Table IV

alloy No. 5 No. 6th Comparative alloy No. 4 No. 7

20 to 100 C. 8.3 7.5 7.85 11.8 200 C. 8.5 8.5 8.65 12.8 300 C. 8.7 9.0 9.10 14.00 400 C. 9.0 10 9.55 15th 500 C. 9.30 11.40 9.90 15.5 600 C. 9.58 12.45 10.20 16 Table V

The coefficient of friction of the alloys according to the invention is in the most varied of media excellent, when played in dry air, in helium, in liquid sodium and in a vacuum.

The results of friction tests to which alloys No. 4, 5, 6 and 7 were subjected are given in Table V below. These tests were performed using a reciprocating friction tester with flat contact surfaces. During the to-and-fro movement, a path length of 30 mm is covered at a speed of 0.5 mm / s, with a load of 11 kg, a pressure of 1.3 bar and a temperature of about 150 ^° C. being used will. In the following table V the abbreviations have the following meanings:

to - initial coefficient of friction
fm = mean coefficient of friction
ff = coefficient of friction towards the end of the investigation

Ap = weight loss of the friction path
Ape = weight loss of the sample.

Specimens
Friction distance sample

Coefficient of friction

Vibrational weight loss
amplitude of the specimens

Tem pe
rature

(C)

Remarks

Alloy No. 4 Alloy No. 4 fo = 0.160 +0.025

fm = 0.150 -

Alloy No. 4 Alloy No. 5 fo = 0.175 +0.025

fm = 0.200 -

Alloy No. 5 Alloy No. 5 fo = 0.180 0.025

fm = 0.175 -

Alloy No. 7 Alloy No. 7 fo = 0.1.55 +0.025

fm = 0.200 (comparison)

Ap ₁ , = 0.0008
Ap ₁ . = 0.0003 150 weak and rule
moderate friction Ap _n = 0.0003
Ap, = 0.0001 150 the same Ap _n = 0.0002
Ap ₁ . = 0.0001 150 the same Ap _n = 0.0003
Ap ₁ . = 0.0001 150 the same

From Fig. 2 it can be seen that the mean friction of alloys Nos. 4 and 5 in liquid Sodium at bOO ° C at a pressure of 3.4 bar and a speed of 1.3 cm / s a very weak, a straight line approximates sinusoidal course. This friction is low and regular. Thus the results obtained are comparable to those obtained with the cobalt alloys (Alloy No. 7) achieved.

Furthermore, the alloys according to the invention withstand corrosion well over long periods of time in the presence of aggressive media. For example, three samples from alloys No. 4, 5 and 6 were corroded ^{in demineralized and degassed water at 350 ° C. for 3 months.} The samples were weighed every month. After one month of investigation, a mean weight increase of 30 mg / dm ^{2 was found in} all of the samples investigated, a value that remains unchanged until the end of the investigation.

The microlotographic examination of sections of corroded samples shows a very fine and regular oxide layer.

The corrosion resistance of the examined alloys according to the invention with high fatigue strength No. 4, 5 and 6 is thus in demineralized and degassed water at 350 ° (satisfactory. At Another investigation gives Alloy No. 7 based essentially on KobjH Comparable results.

Furthermore, the corrosion tests in an acidic medium have shown good results. Table VI illustrates the results obtained with alloys no. 4, 5, 6 and 7 after these alloys had been subjected to the vapors of a solution of 850 cm3 of 12 η-nitric acid and 150 cm ^{3 of} 36 n-sulfuric acid containing 13 g Containing oxalic acid.

Table Vl

sample At first
weight Client
weight Ge
weight
loss Watch
services alloy
No. 4 1.5045 1.0836 28 without cobalt alloy
No. 5 1.8195 1.3223 27.3 without cobalt alloy
No. 6 2.2075 1.6380 25.8 without cobalt alloy
No. 7
(Comparison) 1.8759 decomposed 65% cobalt

oxide and at 500 ° C in the presence of carbon dioxide.

The metallographic examination of the alloys according to the invention was carried out with the aid of an optical Microscope and an electron microscope as well as by anodic dissolution and by an examination carried out with the help of X-rays. These studies show that the structure is eggs Alloys consist of a ferritic-austenitic matrix, which is due to a high content of eutectic massive carbides of the type M? Cj is reinforced.

Furthermore, on cooling, complex cellular carbides of the formula Mi ₁ C _{1 are} precipitated, which contribute to improving the mechanical and physical properties.

As shown in the Figs. 3 and 4 can be seen, which shows the structure of alloy no. 4 in 100 times magnification and showing the texture of Alloy No. 6 magnified 500 times will show the typical morphology of the eutectic carbides of the type M7CJ by a reproduced dense lattice identified by X-ray diffraction.

Furthermore, the amplification of the dislocations at the boundary layer of the matrix to the cellular Carbides are also responsible for the increased durability of these alloys.

The alloys according to the invention have a high density of complex metal carbides, which connected by weak bonds and without residual austenitic areas and are therefore resistant, so that the crystals can be distributed in the form of a homogeneous structure in a stable matrix and against the The influences of temperature and chemical agents are not very sensitive. This mass of evenly distributed carbides allows an advantageous friction hold.

Because of their iron and nickel content, the alloys according to the invention are ferritic-austenitic Matrix which, without being brittle, is sufficiently hard to eat hard or overheat prevent and to ensure that the mass of carbides keeps its small dimensions and perfect remains enveloped by the matrix.

In the case of these alloys, high ratios between the hardness of the carbides and the hardness are achieved the matrix, which is beneficial for achieving good friction values.

The ductility of the matrix allows a certain amount of deformation without local overstresses, which distributes the load, while the carbide skeleton increases the stiffness or strength and the wear limit ensures.

In the following table Vl! are examples of hardness values in N / mm ^ at 100 g of the matrix, the carbides and the ratio of the hardnesses of alloys No. 4, 6 and 7 are given.

It is indisputable that the alloys of the present invention have good resistance even to heat show against corrosion by acids and by water.

The alloys with a high cobalt content are not as durable. It can therefore be seen that the nickel is a cheaper element than the cobalt represents what whole generally concerns the resistance to attack by chemical agents.

In sodium at 600 ⁰ C it is observed an attack, as well as at 500 ° C in the presence of Kohlenmon-

Table VII

alloy

matrix

Carbides

Hardness ratio of carbides to matrix

No. 4 3100 7010 2.3

No. 6 3400 9730 2.8

No. 7 (cobalt) 6210 8050 1.3

The Fig.5, 6 and 7 illustrate the structure of the Alloys No. 4,6 and 7 enlarged 10O.

Due to their good properties, the alloys according to the invention can be used for many purposes in the mechanical-physical or chemical sector, especially when friction problems occur in the dry, in a vacuum, in the cold or at moderately high temperatures (300 to 800 ^° C.) . Due to their low cobalt content (less than 03%), they can be exposed to radiation from neutrons, as they do not involve the risk of being activated in a dangerous manner. Since they do not contain boron, these alloys absorb only little neutrons and can therefore be used to advantage for the production of components of primary circuits of nuclear reactors, for example for the production of pumps, valves, sealing segments, ball bearings, roller bearings and, more generally, for workpieces where the There is a risk of wear and tear due to erosion, friction, corrosion or seizure.

It should also be noted that investigations ^{carried out up to 170 °} C. have shown that their structure is not subject to any change and that the alloys remain homogeneous. They are therefore suitable for the production of workpieces such as pressure relief valves, flaps, ball bearings, etc.

With regard to lower temperatures, interesting investigations were carried out on satellites and thus in the vacuum of space (at about -80 ° C). The workpieces are axes, pinions and small rolling bearings.

These alloys can also be used in the form of application layers to wear objects - as usual - to restore what you can for example by applying fresh material by welding with an oxygen-acetylene torch or by inert gas welding under argon causes

The alloys can also be used in the form of

ίο use powders to apply them to certain sections of To apply against the wear to be protected workpieces, for example with the help of metal spray guns or a plasma jet. The alloys can be engineered in a variety of ways Areas of application are used in which friction phenomena occur and seizure should be avoided at temperatures that can reach 400 to 800 ° C.

Finally, have low temperature studies at

2 (1–172 ° C has shown that the good frictional behavior of the Alloys that make them suitable for manufacturing: Axles, ball bearings or roller bearings that can even be operated without lubrication.

In a space vacuum simulator, the

r> serves to do this. Ball bearings for artificial satellites too test, results were obtained with the alloys according to the invention, which show that the bonding is prevented, which generally occurs with bearings made of cobalt alloys or alloys with high

jo nickel content (of more than 40%) are manufactured.

For this purpose 2 sheets of drawings

Claims (6)

Claims; 1. Supreme with high fatigue strength, characterized in that it consists of 0, i! to 1.9% carbon, 18 to 32% chromium, 1.5 to 8% tungsten, 15 to 40% nickel, 6 to 12% molybdenum, Ci to 3% niobium-tantalum, 0 to 2% silicon, 0 to 3%, manganese, 0 to 3% zirconium, 0 to 3% vanadium, Cl to 0.9% boron, less than 03% cobalt, the remainder iron and manufacturing-related impurities 2. Alloy according to claim 1, characterized in that that they consist of 0.2 to 13% carbon, 18 to 32% chromium, 1.5 to 8% tungsten, 15 to 40% nickel, 6 to 12% molybdenum, 0.1 to 3% niobium tantalum, 0.1 to 2% silicon, 0.1 to 3% manganese, 0.1 to 3% zirconium, 0.1 to 3% vanadium, less than 03% Cobalt, remainder iron and manufacturing conditions Impurities 3. Alloy according to claim 1, characterized in that it consists of 0.2 to 1.9% carbon, 18 to 32% chromium, 1.5 to 8% tungsten, 15 to 40% nickel, 6 to 12% molybdenum, 0.1 to 3% niobium tantalum, 0.1 to 2% silicon, 0.1 to 3% manganese, 0.1 to 3% zirconium, 0.1 to 3% vanadium, 0.1 to 0.9% boron, less than 03% cobalt balance iron and manufacturing-related Impurities 4. Alloy according to claim 3, characterized that they consist of 0.70 to 1% carbon, 24 to 28% chromium, 07 to 1.2% silicon, 0.5 to 1% Manganese, 6 to 9% molybdenum, 1.5 to 1% vanadium, 0.5 to 1% Ni & b-tantalum, 3 to 5% tungsten, 0.5 to 1% Zirconium, 32 to 36% nicice !, less than 0.5% boron, less than 03% cobalt, the rest L.sen and manufacturing-related Impurities. 5. Alloy according to claim 3, characterized in that it consists of UO to 1.50% carbon, 26 up to 30% chromium, 3 to 5% tungsten, 26 to 30% nickel, 6 to 9% molybdenum, 0.5 to 1% niobium tantalum, 0.7 to 1.2% silicon, 0.5 to 1% manganese, 0.5 to 1% zirconium, 1 to 2% vanadium, less than 0.3% Cobalt, less than 0.5% boron, the remainder iron and manufacturing-related impurities. 6. Alloy according to claim 2, characterized in that it consists of 0.20 to 0.50% carbon, 27 up to 31% chromium, 1.5 to 3% tungsten, 16 to 20% nickel, 9 to 12% molybdenum, 0.5 to 1% niobium tantalum, 0.7 to 1.2% silicon, 0.5 to 1% manganese, 0.5 to 1% zirconium, 1 to 2% vanadium, less than 0.3% Cobalt, remainder iron and manufacturing conditions Impurities.